From 7a1dc1ab70b066ee85bc50ef1e5e237ef5d36ca0 Mon Sep 17 00:00:00 2001
From: Suresh Srinivas <suresh@apache.org>
Date: Fri, 24 Aug 2012 17:36:22 +0000
Subject: [PATCH] HDFS-3834. Remove unused static fields NAME, DESCRIPTION and
 Usage from Command. Contributed by Jing Zhao.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1377001 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/hadoop/fs/shell/Command.java   | 18 ++++++++--------
 .../hadoop/fs/shell/TestCommandFactory.java   | 21 ++++++++++++++++++-
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 +++
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Command.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Command.java
index f3f32fcc309..8638e85cd57 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Command.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Command.java
@@ -44,12 +44,12 @@ import org.apache.hadoop.util.StringUtils;
 @InterfaceStability.Evolving
 
 abstract public class Command extends Configured {
-  /** default name of the command */
-  public static String NAME;
-  /** the command's usage switches and arguments format */
-  public static String USAGE;
-  /** the command's long description */
-  public static String DESCRIPTION;
+  /** field name indicating the default name of the command */
+  public static final String COMMAND_NAME_FIELD = "NAME";
+  /** field name indicating the command's usage switches and arguments format */
+  public static final String COMMAND_USAGE_FIELD = "USAGE";
+  /** field name indicating the command's long description */
+  public static final String COMMAND_DESCRIPTION_FIELD = "DESCRIPTION";
     
   protected String[] args;
   protected String name;
@@ -397,7 +397,7 @@ abstract public class Command extends Configured {
    */
   public String getName() {
     return (name == null)
-      ? getCommandField("NAME")
+      ? getCommandField(COMMAND_NAME_FIELD)
       : name.startsWith("-") ? name.substring(1) : name;
   }
 
@@ -415,7 +415,7 @@ abstract public class Command extends Configured {
    */
   public String getUsage() {
     String cmd = "-" + getName();
-    String usage = isDeprecated() ? "" : getCommandField("USAGE");
+    String usage = isDeprecated() ? "" : getCommandField(COMMAND_USAGE_FIELD);
     return usage.isEmpty() ? cmd : cmd + " " + usage; 
   }
 
@@ -426,7 +426,7 @@ abstract public class Command extends Configured {
   public String getDescription() {
     return isDeprecated()
       ? "(DEPRECATED) Same as '" + getReplacementCommand() + "'"
-      : getCommandField("DESCRIPTION");
+      : getCommandField(COMMAND_DESCRIPTION_FIELD);
   }
 
   /**
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/shell/TestCommandFactory.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/shell/TestCommandFactory.java
index ccface37718..db7fc2488c8 100644
--- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/shell/TestCommandFactory.java
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/shell/TestCommandFactory.java
@@ -48,6 +48,10 @@ public class TestCommandFactory {
     factory.addClass(TestCommand3.class, "tc3");
     names = factory.getNames();
     assertArrayEquals(new String []{"tc1", "tc2", "tc2.1", "tc3"}, names);
+    
+    factory.addClass(TestCommand4.class, (new TestCommand4()).getName());
+    names = factory.getNames();
+    assertArrayEquals(new String[]{"tc1", "tc2", "tc2.1", "tc3", "tc4"}, names);
   }
   
   @Test
@@ -72,8 +76,17 @@ public class TestCommandFactory {
     assertNotNull(instance);
     assertEquals(TestCommand2.class, instance.getClass());    
     assertEquals("tc2.1", instance.getCommandName());
+    
+    factory.addClass(TestCommand4.class, "tc4");
+    instance = factory.getInstance("tc4");
+    assertNotNull(instance);
+    assertEquals(TestCommand4.class, instance.getClass());    
+    assertEquals("tc4", instance.getCommandName());
+    String usage = instance.getUsage();
+    assertEquals("-tc4 tc4_usage", usage);
+    assertEquals("tc4_description", instance.getDescription());
   }
-  
+
   static class TestRegistrar {
     public static void registerCommands(CommandFactory factory) {
       factory.addClass(TestCommand1.class, "tc1");
@@ -84,4 +97,10 @@ public class TestCommandFactory {
   static class TestCommand1 extends FsCommand {}
   static class TestCommand2 extends FsCommand {}
   static class TestCommand3 extends FsCommand {}
+  
+  static class TestCommand4 extends FsCommand {
+    static final String NAME = "tc4";
+    static final String USAGE = "tc4_usage";
+    static final String DESCRIPTION = "tc4_description";
+  }
 }
\ No newline at end of file
diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index a89eb51c32a..3cd3efa3bf5 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -200,6 +200,9 @@ Trunk (unreleased changes)
     HDFS-3827. TestHASafeMode#assertSafemode method should be made static.
     (Jing Zhao via suresh)
 
+    HDFS-3834. Remove unused static fields NAME, DESCRIPTION and Usage from
+    Command. (Jing Zhao via suresh)
+
 Branch-2 ( Unreleased changes )
 
   INCOMPATIBLE CHANGES